It is well known to place a block containing soluble substances such as surfactants, disinfectants and fragrances in concentrated form in a lavatory cistern, such that some of the substances dissolve in the water in the cistern between flushes and are dispensed upon flushing into the lavatory bowl.
This method of dispensing the substances into the lavatory bowl has several disadvantages. Firstly, the quantity of the substances that dissolves in the water in the cistern depends on the length of time between flushes, which can vary considerably, and the concentration of the dissolved substances in the water in the cistern can therefore vary considerably from one flush to the next. Secondly, when the lavatory has been flushed, only a small portion of the water from the cistern, and hence only a small portion of the dissolved substances, remains in the bowl, the majority of the dissolved substances therefore being wasted.
International Patent Application No. PCT/US02/15001 (Publication No. WO 02/092924) in the name of S.C. Johnson & Son, Inc. discloses a dispenser for use in a lavatory cistern. The dispenser has an upper reservoir containing a liquid product, a lower dosing chamber containing a floating shuttle, and a first float-operated valve. In use the liquid product trickles down from the reservoir into the dosing chamber. The first float-operated valve is operable to seal the dosing chamber from the lavatory cistern when the cistern is fall of water. The floating shuttle in the dosing chamber forms part of a second float-operated valve that is also operable to seal the dosing chamber from the cistern. When the lavatory is flushed and the water level in the cistern falls below the level of the first float-operated valve, the first float-operated valve opens to allow a dose of the liquid product to flow from the dosing chamber into the remaining water in the cistern. Once the dosing chamber has emptied, the second float-operated valve seals the dosing chamber from the cistern, so as to prevent leakage of the liquid product from the reservoir through the dosing chamber into the cistern until the cistern refills sufficiently for the first float-operated valve to seal the dosing chamber from the cistern.
The dose of the liquid product delivered by the known dispenser is invariant with the length of time between flushes, and is delivered into the cistern just as the cistern empties. It is the water that flows into the lavatory bowl just as the cistern empties that remains in the bowl after flushing. Since the dispenser delivers the dose of the liquid product into this water, most of the liquid product delivered by the dispenser therefore remains in the lavatory bowl after flushing.
On the face of it, the known dispenser therefore appears to have overcome the disadvantages of the known method of dispensing substances into a lavatory bowl.
It is an object of the invention to provide dispensing means that overcomes the disadvantages of the known method of dispensing substances into a lavatory bowl and which is of simpler construction, and hence cheaper to manufacture, than the known dispenser.
While the dispensing means of the invention has been devised to overcome the aforementioned disadvantages of the known method of dispensing substances into a lavatory bowl, it is thought that the dispensing means is suitable for other applications in which it is required to dispense a dose of a first liquid into a second liquid.